I asked Anas bin Malik, "Did the Messenger of Allah declare Madinah a sanctuary?"He replied, "Yes, the area between such-and-such. Whoever introduces a heresy into it or shelters one who does so." Then he said to me, "This one is severe. Upon him is the curse of Allah, the angels, and all people. Allah will accept from him no obligatory worship nor voluntary deed on the Day of Resurrection."
قلت لانس بن مالك: احرم رسول الله المدينة؟ قال: نعم ما بين كذا وكذا، فمن احدث فيها حدثا او اوي محدثا قال: ثم قال لي: هذه شديدة فعليه لعنة الله والملائكة والناس اجمعين. لا يقبل الله منه يوم القيامة صرفا ولا عدلا.
Bukhari narrated it in the chapter on Holding Fast to the Book and the Sunnah (7306), and Muslim in the Book of Hajj (1366:463), both of them through Abdul-Wahid, who said, Asim narrated to us, saying, I said to Anas bin Malik, and he related it. Bukhari added, "Its trees are not to be cut."Muslim also narrated it (1367:464) through another route from Asim with this same chain, and it contains, "Its vegetation is not to be plucked, and whoever does that, upon him is the curse of Allah, the angels, and all people."